Question

Two taps A and B fill an overhead water tank in 12hours and 8 hours respectively. If both of them are opened together, how long would they take to fill the tank completely?

Answer 1

Tap A fills 1 tank in $12$hours

Tap A fills 1 tank in $1$hour=$\frac{1}{12}$

Tap B fills 1 tank in $8$hours

Tap B fills 1 tank in $1$hour=$\frac{1}{8}$

Work done by both the tap =$\frac{1}{12}+\frac{1}{8}$

=$\frac{2+3}{24}$

=$\frac{5}{24}$

It will take $\frac{24}{5}=4\frac{4}{5}$hours, if both of them are opened together.